Anthony Joshua, Great Britain's 29th and final gold medallist at London 2012, may turn out to be a very different sort of fighting champion. In the afterglow of his dramatic victory over the reigning super-heavyweight gold medallist, Roberto Cammarelle, on Sunday the 22-year-old was adamant he would not easily be enticed into the waiting arms of the professional harbour sharks – as Frank Bruno once described them – and, indeed, may defend his title in Rio in four years' time.

That is a long shot. What seems more likely is that he will stay in the amateur ranks for the world championships in Kazakhstan next year and take another look at his career. If he has matured physically and has more success, then that may be the time to sit down with the money men.

Right now the whole world wants a piece. Certainly they are more interested in his wellbeing than when he was arrested for possession of marijuana and running a little wild with his friends on the streets of Watford. Now he is a commodity. He is also very much his own man.

"I will stay in the amateurs as long as possible," he said. "Sometimes it's hard against fighters with more experience than I've got. I want to dominate everyone in the amateurs, become a world champion, become European champion. I'm learning at each tournament. The more tournaments I go to the more I'll improve as a fighter."

Those are remarkable sentiments for a man with an Olympic gold medal hanging round his neck. Nobody could accuse Joshua of arrogance or complacency.

What he has to reflect on on Monday morning is a courageous performance, coming from three points behind in the final round, to have his 32-year-old Italian opponent on unsteady feet under a last-ditch barrage that was more considered than it might have looked from the safe side of the ropes, full of straight rights down the middle and rib-cracking body shots.

The scores were level at 18-18 after nine minutes and went to countback – incorporating the scores of all five judges rather than just the median three – and Joshua had edged it by three points. That was not convincing enough for the Italians, who appealed. When the result of the short hearing was confirmed, the capacity audience, not for the first time over the past fortnight, filled the hall with the most heartfelt roar.

Joshua's quiet features flickered with pride at the medal ceremony and thoughts spread around the arena that this may be the last time we would see him in a vest. Strong rumours suggested Golden Boy Promotions was prepared to offer him a 10-fight deal to turn professional and move to the United States. He would neither confirm nor deny that but said he was staying in the system that had raised him from nowhere to Olympic champion. And Rio in 2016? "I wouldn't mind."

Joshua has enjoyed the Olympic experience outside the ring. "I met a few famous people in the village: Jess [Ennis], Chris Hoy – he's a legend – and Ryan Giggs. And also Nikki Adams... she's a legend now too."

Joshua, who was under pressure at the end of the first round and at the start of the second, found composure in a hurricane. Cammarelle, a Milanese policeman, has been a fine champion for a long time and briefly seemed on the verge of overwhelming an opponent who had had only 43 amateur bouts, losing three.

Joshua admitted he was "in serious pain" but he remembered how he had beaten Cammarelle at the world championships in Baku last year and how he grew stronger from the experience. "I just won't ever give up in there," he said. "I will keep pushing to the last bell. My legs and everything were killing me but I just kept throwing punches, catching him with straight shots down the middle. I never panicked. Sometimes I wanted to stop but my arms were just flying."

As for the close score and the appeal, he said: "My job is to do the fighting in the ring. The judges' job is to decide who the winner is. I've had close fights all over the world and I've lost a couple in my short career. I take it on the chin and I move on. All credit to Cammarelle, he's a great champion."

Four years ago, when Cammarelle was winning his gold medal in Beijing, Joshua was not even boxing. "I wasn't in a gym. I used to play a lot of football – nothing as dedicated and disciplined as when I got into boxing. I don't know where I was, didn't even watch it. I'm happy I got into boxing but it's never been about money. Money does help. My mum pays bills. I've got bills to pay but, thanks to UK Lottery funding, that's the most money I've seen in a long time. I'm happy with that.

"To leave the Great Britain setup just for money would be a big mistake. It's a great experience to be working with such great people, [the head coach] Robert McCracken and his team. I don't want to lose that just for a bit of money thrown in my face. I didn't grow up with loads of money. I learned to cope. I'm happy with life. My mum's a really grounded person, so's my dad. He works really hard. It's not like he's got a lot. It keeps my feet on the ground. These memories are priceless.

"I don't think a gold medal should make the man. This represents the journey. My journey has been so tough. The most I've ever been out with in my back pocket was £250."

Rarely can a man not exactly garlanded with riches (and who has tasted the temptation of an easy earn on the street) have resisted the lure of money so eloquently in the immediate aftermath of his greatest achievement. In a business such as the fight game that sort of morality does not survive persistent scrutiny but Joshua is determined to be different. He is a most unusual, rather special, young man.